DESCRIPTION (Scanned from the Applicant's Abstract): Selenium may play a significant role in cancer prevention. Dietary selenium aids in preventing several types of carcinomas including lung, prostate, and colon. The potency of Se varies with its chemical form. The most effective compounds are rapidly and quantitatively transformed by the body, such as Se-methylselenocysteine, one of the most effective anti-carcinogenic Se-compounds. An inexpensive way to provide dietary Se would be to enrich certain foodstuffs with Se, preferably in the form of Se-methylselenocysteine. We propose to create this type of product by engineering crop plants to accumulate Se -methylselenocysteine. Phase I studies have established the feasibility of altering selenium metabolism in Arabidopsis thaliana by overexpressing ATP sulfurylase, resulting in more efficient assimilation of selenate. Selenocysteine methyltransferase from A. bisulcatus was also expressed in A. thaliana. Further improvements in the ability of these plants to take up and transform selenate involve cloning additional genes involved in Se accumulation. Based on results of the Phase I research, genes involved in Se uptake in the roots and chemical reduction of selenate to selenite in the tissues will be targeted. We will transfer these genes into Brassica juncea, the Indian mustard plants, to produce a commercially viable high Se-methylselenocysteine plant product. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE